Influences of Temperature, pH and Turbidity on the Behavioral Responses of Daphnia magna and Japanese Medaka (Oryzias latipes) in the Biomonitor

Previous studies suggested that the on-line biomonitor could record the behavioral responses of sensitive species under chemical pollution events. However, variation of general water quality parameters, such as temperature, turbidity and pH may also affect the behavioral of the animals that could result in the alarm signal. In this study, the biomonitor equipped with a multi-parameter monitor was used to evaluate the effects of temperature, turbidity and pH on the behavior changes of Daphnia magna and Japanese medaka (Oryzias latipes). The results showed that both motility strength of Daphnia magna and Japanese medaka were inhibited in 5h when the water temperature was lower than 5 degrees C In 50 NTU water body, the decrease of motility strength to 70% of Daphnia magna and Japanese medaka need 10h and 24h separately. In 100 NTU water body, the motility strength of Daphnia magna would decrease 3h later, and it was about 6h for Japanese medaka. If the pH value was lower than 5.5 or higher than 9.0, motility strength decreased significantly in 15h. It is concluded that in the on-line biomonitoring of accidental pollutions, the results of multi-parameter monitor should be considered. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of School of Environment, Beijing Normal University.